From: Ulf Hansson <ulf.hansson@linaro.org>
To: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Geert Uytterhoeven <geert+renesas@glider.be>,
Linux PM <linux-pm@vger.kernel.org>,
Stephen Boyd <sboyd@kernel.org>,
Viresh Kumar <viresh.kumar@linaro.org>,
linux-arm-msm <linux-arm-msm@vger.kernel.org>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
"Rafael J . Wysocki" <rjw@rjwysocki.net>,
Kevin Hilman <khilman@kernel.org>,
Lina Iyer <ilina@codeaurora.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Tony Lindgren <tony@atomide.com>,
Sudeep Holla <sudeep.holla@arm.com>,
"Raju P . L . S . S . S . N" <rplsssn@codeaurora.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v10 24/27] drivers: firmware: psci: Support CPU hotplug for the hierarchical model
Date: Wed, 19 Dec 2018 12:47:53 +0100 [thread overview]
Message-ID: <CAPDyKFoFn=3VzYLriROYEgCT=gbrsjbx8Fc1dktTJ1BdCBxniw@mail.gmail.com> (raw)
In-Reply-To: <20181219111744.GA23393@e107981-ln.cambridge.arm.com>
On Wed, 19 Dec 2018 at 12:17, Lorenzo Pieralisi
<lorenzo.pieralisi@arm.com> wrote:
>
> On Thu, Nov 29, 2018 at 06:46:57PM +0100, Ulf Hansson wrote:
> > When the hierarchical CPU topology is used and when a CPU has been put
> > offline (hotplug), that same CPU prevents its PM domain and thus also
> > potential master PM domains, from being powered off. This is because genpd
> > observes the CPU's struct device to remain being active from a runtime PM
> > point of view.
> >
> > To deal with this, let's decrease the runtime PM usage count by calling
> > pm_runtime_put_sync_suspend() of the CPU's struct device when putting it
> > offline. Consequentially, we must then increase the runtime PM usage for
> > the CPU, while putting it online again.
> >
> > Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> > ---
> >
> > Changes in v10:
> > - Make it work when the hierarchical CPU topology is used, which may be
> > used both for OSI and PC mode.
> > - Rework the code to prevent "BUG: sleeping function called from
> > invalid context".
> > ---
> > drivers/firmware/psci/psci.c | 20 ++++++++++++++++++++
> > 1 file changed, 20 insertions(+)
> >
> > diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
> > index b03bccce0a5d..f62c4963eb62 100644
> > --- a/drivers/firmware/psci/psci.c
> > +++ b/drivers/firmware/psci/psci.c
> > @@ -15,6 +15,7 @@
> >
> > #include <linux/acpi.h>
> > #include <linux/arm-smccc.h>
> > +#include <linux/cpu.h>
> > #include <linux/cpuidle.h>
> > #include <linux/errno.h>
> > #include <linux/linkage.h>
> > @@ -199,9 +200,20 @@ static int psci_cpu_suspend(u32 state, unsigned long entry_point)
> >
> > static int psci_cpu_off(u32 state)
> > {
> > + struct device *dev;
> > int err;
> > u32 fn;
> >
> > + /*
> > + * When the hierarchical CPU topology is used, decrease the runtime PM
> > + * usage count for the current CPU, as to allow other parts in the
> > + * topology to enter low power states.
> > + */
> > + if (psci_dt_topology) {
> > + dev = get_cpu_device(smp_processor_id());
> > + pm_runtime_put_sync_suspend(dev);
> > + }
> > +
> > fn = psci_function_id[PSCI_FN_CPU_OFF];
> > err = invoke_psci_fn(fn, state, 0, 0);
> > return psci_to_linux_errno(err);
> > @@ -209,6 +221,7 @@ static int psci_cpu_off(u32 state)
> >
> > static int psci_cpu_on(unsigned long cpuid, unsigned long entry_point)
> > {
> > + struct device *dev;
> > int err;
> > u32 fn;
> >
> > @@ -216,6 +229,13 @@ static int psci_cpu_on(unsigned long cpuid, unsigned long entry_point)
> > err = invoke_psci_fn(fn, cpuid, entry_point, 0);
> > /* Clear the domain state to start fresh. */
> > psci_set_domain_state(0);
> > +
> > + /* Increase runtime PM usage count if the hierarchical CPU toplogy. */
> > + if (!err && psci_dt_topology) {
> > + dev = get_cpu_device(cpuid);
>
> I do not like adding this code in the cpu_{on/off} method themselves, I will
> have a look at the patchset as whole to see how we can restructure it.
Any suggestions are welcome, of course. This was the best and most
simple option I could come up with.
Another option, could be to simply to remove the runtime PM deployment
from psci_cpu_off|on() altogether and just live with that limitation
for now. That works for me as well.
>
> More to the point, using cpuid as a logical cpu id is wrong, it is a
> physical id that you should convert to a logical id through
> get_logical_index().
Oh, didn't know that, thanks for pointing that out!
>
> Lorenzo
>
> > + pm_runtime_get_sync(dev);
> > + }
> > +
> > return psci_to_linux_errno(err);
> > }
> >
> > --
> > 2.17.1
> >
Kind regards
Uffe
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next prev parent reply other threads:[~2018-12-19 11:48 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-29 17:46 [PATCH v10 00/27] PM / Domains: Support hierarchical CPU arrangement (PSCI/ARM) Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 01/27] PM / Domains: Add generic data pointer to genpd_power_state struct Ulf Hansson
2018-12-18 10:39 ` Daniel Lezcano
2018-12-18 11:53 ` Ulf Hansson
2019-01-11 10:52 ` Rafael J. Wysocki
2018-11-29 17:46 ` [PATCH v10 02/27] PM / Domains: Add support for CPU devices to genpd Ulf Hansson
2018-12-19 9:53 ` Daniel Lezcano
2018-12-19 10:02 ` Ulf Hansson
2019-01-11 10:54 ` Rafael J. Wysocki
2018-11-29 17:46 ` [PATCH v10 03/27] timer: Export next wakeup time of a CPU Ulf Hansson
2019-01-11 11:06 ` Rafael J. Wysocki
2019-01-16 7:57 ` Ulf Hansson
2019-01-16 10:59 ` Rafael J. Wysocki
2019-01-16 12:00 ` Ulf Hansson
2019-01-25 10:04 ` Ulf Hansson
2019-01-25 10:18 ` Rafael J. Wysocki
2018-11-29 17:46 ` [PATCH v10 04/27] PM / Domains: Add genpd governor for CPUs Ulf Hansson
2018-12-19 9:54 ` Daniel Lezcano
2018-12-19 10:09 ` Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 05/27] dt: psci: Update DT bindings to support hierarchical PSCI states Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 06/27] of: base: Add of_get_cpu_state_node() to get idle states for a CPU node Ulf Hansson
2018-12-19 11:05 ` Daniel Lezcano
2018-11-29 17:46 ` [PATCH v10 07/27] cpuidle: dt: Support hierarchical CPU idle states Ulf Hansson
2018-12-19 11:20 ` Daniel Lezcano
2018-11-29 17:46 ` [PATCH v10 08/27] ARM/ARM64: cpuidle: Let back-end init ops take the driver as input Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 09/27] drivers: firmware: psci: Move psci to separate directory Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 10/27] MAINTAINERS: Update files for PSCI Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 11/27] drivers: firmware: psci: Split psci_dt_cpu_init_idle() Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 12/27] drivers: firmware: psci: Simplify state node parsing Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 13/27] drivers: firmware: psci: Support hierarchical CPU idle states Ulf Hansson
2018-12-19 12:11 ` Daniel Lezcano
2018-12-19 12:53 ` Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 14/27] drivers: firmware: psci: Simplify error path of psci_dt_init() Ulf Hansson
2018-12-19 12:08 ` Daniel Lezcano
2018-11-29 17:46 ` [PATCH v10 15/27] drivers: firmware: psci: Announce support for OS initiated suspend mode Ulf Hansson
2018-12-20 13:11 ` Daniel Lezcano
2018-11-29 17:46 ` [PATCH v10 16/27] drivers: firmware: psci: Prepare to use " Ulf Hansson
2018-12-20 14:08 ` Daniel Lezcano
2018-12-20 15:41 ` Ulf Hansson
2018-12-20 17:16 ` Daniel Lezcano
2018-11-29 17:46 ` [PATCH v10 17/27] drivers: firmware: psci: Prepare to support PM domains Ulf Hansson
2018-12-20 14:19 ` Daniel Lezcano
2018-12-20 15:49 ` Ulf Hansson
2018-12-20 18:06 ` Daniel Lezcano
2018-12-20 21:37 ` Ulf Hansson
2018-12-21 7:15 ` Daniel Lezcano
2018-11-29 17:46 ` [PATCH v10 18/27] drivers: firmware: psci: Add support for PM domains using genpd Ulf Hansson
2018-12-03 16:37 ` Lina Iyer
2018-12-03 20:03 ` Ulf Hansson
2018-12-20 14:35 ` Daniel Lezcano
2018-12-20 21:09 ` Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 19/27] drivers: firmware: psci: Add hierarchical domain idle states converter Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 20/27] drivers: firmware: psci: Introduce psci_dt_topology_init() Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 21/27] drivers: firmware: psci: Add a helper to attach a CPU to its PM domain Ulf Hansson
2018-12-04 18:45 ` Lina Iyer
2018-12-06 9:15 ` Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 22/27] drivers: firmware: psci: Attach the CPU's device " Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 23/27] drivers: firmware: psci: Manage runtime PM in the idle path for CPUs Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 24/27] drivers: firmware: psci: Support CPU hotplug for the hierarchical model Ulf Hansson
2018-11-29 22:31 ` Lina Iyer
2018-11-30 8:25 ` Ulf Hansson
2018-11-30 20:57 ` Lina Iyer
2018-12-19 11:17 ` Lorenzo Pieralisi
2018-12-19 11:47 ` Ulf Hansson [this message]
2018-11-29 17:46 ` [PATCH v10 25/27] arm64: kernel: Respect the hierarchical CPU topology in DT for PSCI Ulf Hansson
2018-11-29 17:46 ` [PATCH v10 26/27] arm64: dts: Convert to the hierarchical CPU topology layout for MSM8916 Ulf Hansson
2018-11-29 17:47 ` [PATCH v10 27/27] arm64: dts: hikey: Convert to the hierarchical CPU topology layout Ulf Hansson
2018-12-17 16:12 ` [PATCH v10 00/27] PM / Domains: Support hierarchical CPU arrangement (PSCI/ARM) Ulf Hansson
2019-01-11 11:08 ` Rafael J. Wysocki
2019-01-03 12:06 ` Sudeep Holla
2019-01-16 9:10 ` Ulf Hansson
2019-01-17 17:44 ` Sudeep Holla
2019-01-18 11:56 ` Ulf Hansson
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